RTD : The Treasure of Death Valley
I talked with Ximen Xianji in Zhengzhou and deliver the letter to Yizheng in the Twin Towers. He gave me 3 Passes of Death Valley. I went to kill Dream, Faced Buddha. In COF I found 3 Pots and broke them until I found the Secret Box . Got as reward an elixir and a Manual of Wu-Tang: Advanced III.